Use case or problem
If I’m in “writing mode” I want to hide both of the sidebars, because I’m only interested in the notes on the screen.
But when I’m in “navigating mode” (e.g. I’m searching / referring to my files / looking at graphs and tags etc), then those sidebars on the left and right are useful.
Proposed solution
Include an option to toggle both sidebars as a hotkey.
Current workaround
Toggle both sidebars individually or click “collapse / expand” manually 
Related feature requests
Possibly related to: Provide default shortcuts for more hotkeys